Polycapillary x-ray optic spectral gain and transmission

Polycapillary x-ray optics are gaining increased attention as their transmi ssion characteristics and manufacturing difficulties are better understood. This paper reports experimental results obtained with an optic that was de signed for use with both Mo K alpha (17.5 keV) and Cu K alpha (8 keV), The spectral gain function from 4 to 30 keV was determined from measurements ma de with an Si(Li) detector, and the results were compared with Monte Carlo simulations. The spatial variation in the spectral transmission was examine d with both an Si(Li) detector and a magnifying x-ray CCD camera. The resul ts show that even though the individual capillaries are tapered, their perf ormance is well described by a simple parabolic relationship between the ra dius of curvature and the maximum energy transmitted derived for capillarie s of constant diameter. Copyright (C) 1999 John Wiley & Sons, Ltd.